1. Field of the Invention
The present invention relates to electronic devices, such as mobile information terminals and mobile personal computers.
2. Description of the Related Art
For example, as described in Japanese Patent Application Laid-Open (Kokai) Publication No. 2007-210133, a mobile electronic device equipped with a printer is known. This device is comprised with an opening and closing apparatus in which a printer cover conceals a recording paper storage section formed in the device case with an openable/closable cover.
This type of cover opening and closing apparatus is configured such that one end portion of the cover is rotatably attached to the device case and the other end portion of the cover is positioned on the opposite side in the rotational center of this cover. A platen roller which faces the print head in the device case is removably attached to a rotation shaft enabling free rotation. The rotation shaft of the platen roller is locked by a lock groove provided in the device case when the cover is closed which conceals the recording paper storage section.
In this structure, a hook section in a flat spring shape that resiliently projects into the locking groove is provided in the device case. Accordingly, when the cover is closed, which conceals the recording paper storage section, the rotation shaft of the platen roller is inserted into the locking groove against the resilient force of the hook section, whereby the hook section resiliently returns and locks the rotation shaft into the locking groove. Therefore, the cover opening and closing apparatus locks the rotation shaft in a state where the cover is closed.
However, this type of cover opening and closing apparatus has a problem as follows: when the hook section in a flat spring shape has weak resilient force, the rotation shaft of the platen roller may detach from the locking groove of the device case during use, whereby the cover may open; when the hook section in a flat spring shape has a strong resilient force, the rotation shaft of the platen roller cannot be easily withdrawn from the locking groove of the device case when the cover is opened, whereby opening and closing operations of the cover cannot be easily performed.
To solve this problem, the above-described cover opening and closing apparatus in Japanese Patent Application Laid-Open (Kokai) Publication No. 2007-210133 is configured such that an operating lever is rotatably attached to the device case and provided with a lock tab. As a result, by the operating lever being rotated and the lock tab being retractably inserted into the locking groove of the device case, the rotation shaft of the platen roller is locked into the locking groove of the device case by the lock tab.
In this type of a cover opening and closing apparatus, in order that the cover is opened, the operating lever is rotated and the lock tab is disengaged from within the locking groove of the device case, whereby the lock on the rotation shaft of the platen roller inserted into the locking groove of the device case is released. And then, the cover is rotated in an opening direction in this state, whereby the rotation shaft is pulled out of the locking groove. As a result, the cover can be opened.
However, in this type of cover opening and closing apparatus having an operating lever, the cover cannot open merely by rotating the operating lever and releasing the lock on the rotation shaft of the platen roller by the lock tab. In other words, the cover cannot open unless the cover is rotated in the opening direction in a state where the lock is released, whereby the rotation shaft is pulled out of the locking groove. That is, the lock releasing operation and the cover opening operation for opening the cover are separate operations. Therefore, there is a problem in that the opening and closing operations of the cover are troublesome, and opening and closing operability of the cover is poor.